Design is deliberate development of activity through the creation of new artefacts and their introduction into a given activity system Ñ it is the (re-) creation of conditions for life. Design of computer artefacts is the develop-ment of the entire work setting, thus general notions of developdevelop-ment and progress are important elements in understanding design of computer arte-facts.
Analytically, design activity is when a designing subject shapes the design object by means of some design artefacts. The design object is the artefacts changed or created in designÑthe outcome which design activity is directed to. The design object is a part of the deliberately shaped environment, or conditions for human life: houses, cars, word-processors, and furniture. The designing subject is almost always a collective subject. Some of the members of this subject can be professional designers who design the conditions for the lives of somebody else, and others can be members of the praxis that the design object is intended to mediate. Design artefacts are artefacts that me-diate the design activity; they are utilised but not consumed during the pro-cess. They serve as conditions or environment for the design propro-cess. Design artefacts can thus be opposed to materials. Examples of design artefacts are
programming languages, CASE-tools, specification standards, and systems development methods. A prototype can both be understood as a design arte-fact and as object of design. Design artearte-facts are mediating three main sign functions: getting knowledge and understanding about what is de-signed, i.e. conception; communicating and co-operating during this process;
and constructing the new artefacts forming the considered world. Often a de-sign artefact is intended to support just one of these elements: an editor is used for writing code, a future workshop is used in order to understand the problem domain, memos are used for communication, and so on.
designing subject
design
object (outcome) design
artefacts
Figure 9: The relation between design subject, design object, and design artefact in naive activity theory terms.
Software is basically a moving target. From the point of view of activity the-ory, it is an obvious problem for any design discipline that the object of de-sign will not take its final form before it becomes part of the object activity;
furthermore the object activity is changed through the introduction of the new artefact. In the design of computer artefacts, the situation is compli-cated even more because computer artefacts are composed of symbols, or signs, which have meaning and makes sense in ways constituted in the situ-ation of use. This unpredictability is a basic feature of design of computer artefacts and can only be remedied through iterative design processes in-volving representatives from the use domain.
The prototyping session (e.g. B¿dker & Gr¿nb¾k 1996) can serve as a gen-eral metaphor for design. In idealised terms, prototyping is a process where one or more designers work together with one or more prospective users on developing new computer support for the users. Based on some sort of vision or an analysis of the usersÕ needs the system developers build the first pro-totype. The prototype is tried out in work (like) situations with the users and gradually adjusted to fit the (renewed) praxis. Users and designers are fundamentally unable to understand each other, but during the prototyping
session they build a common understanding which, however, is only present as the final prototype.12
Thus, design is basically heteropraxial, i.e., involving heterogeneous groups of people with different backgrounds and different motivation for participat-ing in the process.
In the framework of activity theory outlined above, design can be understood as the instrument producing activity in relation to the considered use activ-ity, and the use activity can be understood as object activity for the design activity. This analysis, however, does not capture the intertwined character of the prototyping session proposed as a general metaphor for design. What tie the involved activities together in design are the involved artefacts; the design artefacts and the artefacts which are object of the design process. In the design situation these artefacts become boundary objects, constituting a boundary zone of design, where users and designers meet to change the world together but not necessarily understand each other (see figure 10).
Design
Figure 10: Heteropraxiality of design: by applying the notion of boundary ob-ject we get this picture. The figure is the composition of two triangles of (design) activity, the boundary objects and boundary artefacts of design
con-stitute a boundary zone.
This analysis of design as being heteropraxial is primarily a descriptive one outlining general features of design. However, it also states the normative ideal of active involvement and codetermination by all involved parties as the basic form of unrestrained design; cooperative, or participatory, design becomes the ideal. Basically, participatory design occurs when users are
ac-12 Actual prototyping always includes initial analysis of the considered activity system as a basis for the construction of the first prototype. The purpose in the present context is to point to fundamental characteristics of design in general, not to discuss rapid prototyping.
tive subjects in the design activity, which is opposed to the mere involve-ment of users as test objects. Thus, much of the so-called participatory de-sign reported in the literature should rather be labelled extended user test-ing.